error about iracket HOT 4 OPEN

If I paste the code above into a Jupyter notebook cell and run it, there are no errors. There is also no output.

from iracket.

If I paste the code above into a Jupyter notebook cell and run it, there are no errors. There is also no output.

sorry , i lose the below

(define (integers-starting-from n)
(cons-stream n (integers-starting-from (+ n 1))))

(define integers
(integers-starting-from 1))

;(display-line (stream-ref integers 0))
(let ((x (stream-subseq integers 10000 10010)))
(display-stream x))

(define odd-numbers
(stream-filter odd? integers))

(display-stream (stream-subseq odd-numbers 50 60))

;(let ((x (cons-stream 1 (cons-stream 2 '(3)))))
; (display-stream x))

(define (stream-add s n)
(stream-map (lambda (x)
(+ x n)) s))

(define (add-streams s1 s2)
(stream-map + s1 s2))

(define fib
(cons-stream 1
(cons-stream 1
(add-streams fib
(stream-cdr fib)))))

(display-stream (stream-subseq fib 150 160))

(define (divisible? x y)
(= (remainder x y) 0))

(divisible? 10 2)

(define (sieve stream)
(cons-stream
(stream-car stream)
(sieve (stream-filter
(lambda (x)
(not (divisible? x (stream-car stream))))
(stream-cdr stream)))))

(define primes
(sieve (integers-starting-from 2)))

(display-stream (stream-subseq primes 1000 1010))

from iracket.

I haven't run the new example, but I expect you're running into problem called "the top level is hopeless". Here's a smaller example:

(require racket)
;; range : Real Real -> Real
;; compute the length of an interval
(define (range a b) (if (<= a b) (- b a) (range b a)))
(range 5 10) ;; => 5
(range 10 5) ;; => '(5 6 7 8 9)

If you google "racket the top level is hopeless" you should find some discussions. I'm working on an addition to the IRacket docs that warns about this issue. Meanwhile, the best way to avoid it is to avoid redefinitions --- especially, avoid redefining names imported from modules. You can probably do that here by removing (require racket) and requiring the specific modules that you need.

from iracket.

I haven't run the new example, but I expect you're running into problem called "the top level is hopeless". Here's a smaller example:

(require racket)
;; range : Real Real -> Real
;; compute the length of an interval
(define (range a b) (if (<= a b) (- b a) (range b a)))
(range 5 10) ;; => 5
(range 10 5) ;; => '(5 6 7 8 9)

If you google "racket the top level is hopeless" you should find some discussions. I'm working on an addition to the IRacket docs that warns about this issue. Meanwhile, the best way to avoid it is to avoid redefinitions --- especially, avoid redefining names imported from modules. You can probably do that here by removing (require racket) and requiring the specific modules that you need.

thank you for you reply .

the problem is Lazy Evaluation .

• racket : supported by like syntax-rules () , i can run my example work well .
• iracket : does not supported , i do not know why, the result is, endless loop .

from iracket.